How to Fix Cassandra Consistency Issues using Read Repair

How to Fix Cassandra Consistency Issues using Read Repair. Why Consistency Issues or C in CAP theorem. As many of you probably know, Cassandra is an AP big data storage.

Why Consistency Issues or C in CAP theorem

As many of you probably know, Cassandra is an AP big data storage. In other words, when a network partition happens, Cassandra remains available and relaxes the Consistency property. It is always said that it is eventually consistent or, in other words, it will be consistent at some point in time in future.

The important things to know which is not really obvious are:

• The cluster does *become *inconsistent pretty often. Sure, there are many things influencing the stability of the cluster, such as proper configuration, dedicated resources, production load, professionalism of the ops guys etc, but the fact is the probability the nodes are going down from time to time and therefore the data become inconsistent are really high.
• The cluster does NOT become consistent again automatically. *This is something which goes against the god feeling towards the modern and mature distributed systems. Unless you have the enterprise version of Datastax and enable one the latest feature of DSE v6 you have to fix the inconsistency issues *manually.

Ways to Fix Inconsistency

Fortunately, there are ways to fix the inconsistency issues. There a couple of options here:

• nodetool repair tool. This is probably the main and default method to use. Running the command on a node which was down for all the tables or specific ones. One caveat though is: all the nodes should be UP while you are running the command.
• read repair Cassandra feature. This is an important feature meaning, during the read requests the cluster organism is repairing itself, to be more precise it repairs the proper data replicas. If the replicas involved in a read requests are not consistent they are being aligned again

nodetool-repair big-data cassandra data-science

An extensively researched list of top microsoft big data analytics and solution with ratings & reviews to help find the best Microsoft big data solutions development companies around the world.

In this article, see the role of big data in healthcare and look at the new healthcare dynamics. Big Data is creating a revolution in healthcare, providing better outcomes while eliminating fraud and abuse, which contributes to a large percentage of healthcare costs.

‘Data is the new science. Big Data holds the key answers’ - Pat Gelsinger The biggest advantage that the enhancement of modern technology has brought

We need no rocket science in understanding that every business, irrespective of their size in the modern-day business world, needs data insights for its expansion. Big data analytics is essential when it comes to understanding the needs and wants of a significant section of the audience.

Online Data Science Training in Noida at CETPA, best institute in India for Data Science Online Course and Certification. Call now at 9911417779 to avail 50% discount.